Fundamentally, I am interested in how galaxy evolution is shaped by environment. We can best understand this by examining galaxies at high and low redshift and at a range of wavelengths. Much of my recent research investigates the role that removal of gas plays in transforming Virgo Cluster galaxies from blue to red. To do this, I utilize multiple techniques, including optical spectroscopy, radio interferometry, optical imaging, and UV imaging. Leveraging modern stellar population models, we can start to understand how the stars in galaxies are affected by the removal of gas.

VIVA (VLA Imaging of Virgo in Atomic Gas) is an ongoing multi-wavelength project seeking to understand the effect of cluster processes on galaxies in the nearby Virgo cluster. The initial VIVA data consisted of HI maps for 52 spiral galaxies in the Virgo Cluster. In addition, we have a wide array of ancillary data, including optical imaging, Spitzer infrared imaging, UV imaging, and optical spectroscopy.

NGC 4402 is one of the best-known examples of an ongoing interaction between the interstellar medium (ISM) of the galaxy and the intracluster medium (ICM) of the Virgo Cluster. The galaxy has two linear dust filaments that are aligned with each other and a radio continuum tail, strongly suggesting this galaxy is currently experiencing ICM pressure.

Our study of ten stripped spiral galaxies in the Virgo Cluster has revealed that gas stripping is much more complex than simple models would suggest. Galaxies are stripped at far greater cluster radii than is typically assumed. Constraints from the stellar populations in the inner stripped disk of these galaxies shows that star formation ended too recently for the galaxies to be stripped in the core and travel to their current location (see figure).

NGC 4522 is a strong case for ongoing ISM-ICM interaction. By looking at the outer disk of this galaxy, beyond where star formation has been cut off, we have determined that star formation ended very recently in this galaxy, despite its large distance from the cluster center. Moreover, the outer disk spectrum of this galaxy is similar to "post-starburst" k+a galaxies observed at higher redshift, suggesting that stripping can create apparent "post-starburst" signatures.

Studying Virgo galaxies in detail gives us an important window into galaxy evolution. However, the vast majority of galaxies in the Universe cannot be studied in this way. We are currently completing a study on how Broadband Colors of Virgo Cluster galaxies are affected by removal of neutral HI gas.